There has been a plastic bag including side gusset portions, as disclosed in Japanese Patent Publication No. 3,733,085. In the publication, an apparatus is arranged to successively making plastic bags by supplying continuous webs from rolls. The plastic bag is called a side gusset bag which includes panel portions and side gusset portions. The panel portions are superposed on each other to have opposite side edges along which the side gusset portions extend. The side gusset portions are folded into halves and interposed between the panel portions. The plastic bag can therefore be enlarged by the side gusset portions to obtain an increased capacity.
The plastic bag further includes a bottom gusset portion in addition to the panel portions and the side gusset portions. The continuous webs comprise panel, side gusset and bottom gusset webs. The apparatus is arranged to supply the panel, side gusset and bottom gusset webs from the rolls so that the panel portions are formed of the panel web while the side gusset portions are formed of the side gusset web. The bottom gusset portion is formed of the bottom gusset web. The continuous webs may comprise panel and side gusset webs. The apparatus is arranged to supply the panel and side gusset webs from the roils so that the panel and bottom gusset portions are formed of the panel web while the side gusset portions are formed of the side gusset web, as disclosed in Japanese Patent Publication No. 3,655,627.
In the meantime, it is often that the side gusset bag is considerable large. In this connection, the side gusset bag is too heavy to carry it when being filled with content. It is therefore required to make the side gusset bag provided with a handle to carry the side gusset bag by the handle.
By the way, it is known to wrap content with a plastic film, which is provided with a handle, as disclosed in Japanese Laid-Open Patent Publication No. H02-109,868. In the publication, the plastic film has an outer surface to which a strip sheet is adhered so that the handle can be formed of the strip sheet.
It is therefore conceivable to make a strip sheet adhered to the outer surface of the side gusset bag so that a handle can be formed of the strip sheet in the apparatus for successively making side gusset bags. However, the problem is what adhesive agent to utilize. A hot-melt or instant adhesive agent merely has an adhesive strength not enough to carry the side bag by the handle when the strip sheet is adhered to the outer surface of the side gusset bag with the hot-melt or instant adhesive agent so that the handle can be formed of the strip sheet. The handle must be peeled and separated off by weight of the side gusset bag which is too heavy, as described previously.
On the other hand, a strong adhesive agent has been commercially available. It is defined herein that the strong adhesive agent is a particular adhesive agent having an adhesive strength increased. However, it is often that the strong adhesive agent needs a curing time. In this connection, there appears almost no adhesive strength until the curing time elapses after applying the strong adhesive agent to one of the opposite surfaces of the strip sheet and making the strip sheet adhered to the outer surface of the side gusset bag. It is therefore required to keep the strip sheet and the side gusset bag from being moved for at least a time of 10 minutes after the strip sheet is adhered. The strip sheet may be deviated or peeled off if the side gusset bag is fed at a high speed before the above time elapses. It is therefore unpractical to make the strip sheet adhered with the strong adhesive agent needing the curing time in the apparatus successively making side gusset bags.
It is therefore an object of the invention to overcome the problems of adhesive strength and curing time when a handle is formed of a strip sheet adhered with a certain adhesive agent in an apparatus for successively making plastic bags.